Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Basic Instrument Flight — Theory

CASA Recreational Pilot License (Aeroplane) — CASA Sample Syllabus Lesson 26, Theory

All text and presenter notes in this briefing are licensed under Creative Commons BY-SA 4.0. More info

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Do you remember being dizzy as a kid?

Even if it's been years since you've spun yourself on the spot and tried to walk in a straight line, most of us remember the experience:

  • What is causing the disorientation when we're dizzy like this?

Or if you're a diver, you may have experienced not knowing which way is up or down?

Hopefully you will never have effects this strong in an aeroplane, but the disorientation can be debilitating nonetheless. Let's be prepared for the possibilities!

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

What if you couldn't see the horizon?

One of the more dangerous possibilities in a visual flight is that you fly into clouds and, as a result, lose your horizontal reference - the horizon.

Our inner ear's balance sense can be tricked very convincingly once our eyes lose a fixed reference point:

  • We can feel that we're going up when really we're accelerating (dangerous if you "correct" and are low to the ground),
  • We can feel that we're flying wings-level when we're actually banking.

How we avoid being tricked is what this lesson is about.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

So how do we fly without it?

We already have instruments that show an artificial horizon, airspeed, height and heading. Today we'll be learning:

  • How to read them as a system, not one at a time
  • Why your senses can lie to you once the horizon is gone
  • What to do if you ever find yourself in cloud unexpectedly
  • How to recognise and recover from an unusual attitude

Trust the instruments over your senses.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Theory Lesson Overview

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Learning Objectives

By the end of this session, our aim is to be able to:

  • Describe the control-and-performance method of reading the panel, and explain why a continuous scan matters
  • Describe at least three sensory illusions that can mislead a pilot without outside visual reference
  • Explain the dangers of inadvertent flight into cloud, and outline the actions to take if it happens
  • Describe the instrument indications and recovery for a nose-high and a nose-low unusual attitude
  • First experience of flying by sole reference to instruments, including simulated unusual attitude recovery
Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Waypoint 1 — Flying by the Instruments

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

First — your workbook

  • What powers the Attitude Indicator and Direction Indicator? What's electric instead? Why?
  • In Australia, what's ONUS? What's SAND?
  • Any questions before we build on this?
Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Two ways to read the panel: control and performance

  • Control instruments — tell you what you've set: the Attitude Indicator (pitch and bank) and the power indicators (tachometer / manifold pressure)
  • Performance instruments — tell you the result: airspeed, altitude, rate of climb or descent, heading, balance

Set the control instruments to a known attitude and power combination, then confirm the result on the performance instruments.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

right large A photograph of a light aircraft's "six pack" instrument panel. Top row, left to right: Airspeed Indicator, Attitude Indicator, Altimeter. Bottom row, left to right: Turn Coordinator, Direction Indicator, Vertical Speed Indicator.

The six-pack group

  • Control — the Attitude Indicator (top centre), plus the power gauge (tachometer / manifold pressure) elsewhere on the panel, not pictured here
  • Performance — the other five: Airspeed Indicator, Altimeter, Vertical Speed Indicator, Direction Indicator, Turn Coordinator

"Six Pack flight instruments" by Mawilson, licensed CC BY-SA 3.0

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Scan technique — don't stare, don't chase

We'll use a simple hub-and-spoke scan technique:

  • Keep your eyes moving — fixating on any one instrument is a fixation away from all the others
  • A simple scan: Attitude Indicator in the centre (the hub), glance out to each performance instrument (the spokes) and back
  • Make a small correction, then wait for the aircraft to settle before judging the result — chasing an instrument that's still lagging (remember your workbook) only makes the oscillation worse
  • CASA calls this scan technique appropriate to the fitted instruments and phase of flight [IFF 4(a)]
Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Waypoint 2 — Trust Your Instruments

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Why your senses can lie to you

Hopefully you've already watched the excellent Spatial Disorientation video from Gold Seal Flight Training as part of your workbook exercise. To summarise:

  • Your inner ear (the vestibular system) senses rotation and acceleration — not attitude — and it's easily fooled once you can't see the horizon
  • A slow, sustained turn can stop feeling like a turn at all
  • Rapid acceleration can feel like a climb; deceleration can feel like a descent

If your senses and your instruments disagree, believe the instruments.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Three illusions worth knowing

Illusion Feels like What's actually happening
The leans Banked when you're level (or level when you're banked) A slow or prolonged turn stops registering in the inner ear; levelling out feels like banking the other way
Graveyard spiral A gentle, level turn — no sensation of banking A prolonged turn desensitises the inner ear while the aircraft is actually descending steeply and tightening
Somatogravic illusion A strong pitch-up (climbing) sensation Rapid acceleration (full power, or a go-around) is felt as a climb, tempting a dangerous nose-down correction

For another deeper dive on the Leans illusion, see the Flight Club video The LEANS ILLUSION. How pilots get disoriented..

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

See it for yourself

There are many investigation reports about Somatogravic illusion, including a tragic accident a few years ago of an Australian pilot in the US who took off after dark without much instrument experience (NTSB report for December 2022 accident in Venice, Florida)

The Pilot's Handbook of Aeronautical Knowledge, chapter 17 has a thorough list of these and more illusions if you'd like to read more.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

The only reliable fix

  • Trust the instruments over your senses, every time you're without outside visual reference
  • Illusions are strongest when your head moves while turning (looking down at a chart, reaching for something) — keep head movements smooth and minimal under the hood
  • If a sensation and an instrument disagree, believe the instrument — and say it out loud; naming it helps break the illusion's grip

Believing your senses over the instruments is how a perfectly serviceable aeroplane flies into the ground. It has happened, repeatedly, to experienced pilots.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Waypoint 3 — Avoiding and Escaping IMC

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

The danger of VFR flight into cloud

  • As a VFR pilot, you are not trained or endorsed to fly solely on instruments in real cloud
  • Without outside reference, the illusions we just covered can develop within seconds
  • VFR-into-IMC is one of the most consistently fatal categories of general aviation accident — about 1 in every 9 reported occurrences in Australia (2015–2025) resulted in a fatality

The safest response to deteriorating weather is the one made before you're in it: turn back, or land, while you still have the choice.

The ATSB's Avoidable Accidents number 4 specifically looks at Accidents involving pilots in IMC,
which identifies in the introduction that:

the chances of a VFR into IMC encounter increased as the flight progressed, with
the maximum chance occurring during the final 20 per cent of the flight distance.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Avoiding it in the first place

  • Check the actual and forecast weather thoroughly before you fly — not just at departure, but along the route and at any alternate
  • Set personal minimums (cloud base, visibility) in advance, and stick to them under pressure
  • Identify escape routes and alternates during planning, not in the moment
  • Recognise external pressure to press on ("get-there-itis") as a threat in itself

A non-fatal but telling case: a pilot flying Bankstown to Orange in January 2025 entered cloud shortly after take-off — ATSB found insufficient pre-flight weather consideration and self-imposed pressure to proceed both contributed. ATSB AO-2025-003

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

If you find yourself in cloud anyway

The standard actions, in order:

  1. Maintain control — wings level, on the instruments, immediately
  2. Turn back — a gentle rate-one turn onto a reciprocal heading, back the way you came, toward known VMC
  3. Tell someone — a radio call, and the transponder code briefed for the situation
  4. Descend only if safe — only if you know the terrain and it will genuinely help; otherwise hold height and turn first

The turn back is the single most important action. Most inadvertent-IMC accidents happen because the pilot pressed on instead of turning around immediately.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Waypoint 4 — Unusual Attitudes

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Recognising an unusual attitude

Two broad types, told apart mainly by the airspeed:

Nose-high Nose-low
Airspeed Low and decreasing High and increasing
Altimeter Increasing Decreasing
VSI Climbing Descending
Danger Approaching the stall Overspeed / spiral dive

Airspeed is your fastest clue: decreasing means nose-high, increasing means nose-low.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Recovery, in order

Nose-high (low or decreasing airspeed):

  1. Power — apply full power
  2. Roll the wings level
  3. Ease forward to lower the nose to the level-flight attitude
  4. Once settled, adjust power and re-trim

Nose-low (high or increasing airspeed):

  1. Power — close the throttle
  2. Roll the wings level
  3. Ease back smoothly to raise the nose to the horizon — no snatch
  4. Once settled, resume cruise power and re-trim

Power, then wings level, then pitch — in that order, for either case. Rolling level before you pitch is what stops a nose-low recovery turning into a spiral dive (Lesson 18).

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Flying it on the full panel

  • Today we fly with the full instrument panel available — every instrument working, cross-referenced continuously
  • The Attitude Indicator gives the fastest, most direct picture of the unusual attitude — but always confirm with the ASI, altimeter and VSI, since the AI can topple past its limits (typically 60° pitch / 90° roll on this class of aircraft)
  • Ignore the sensations — they will likely disagree with what the instruments show. Believe the instruments.
Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Further reading

The Pilot Institute has a good article on How to Recover from Unusual Attitudes which goes over much of recognising and recovering from unusual attitudes.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Waypoint 5 — Recap

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

What do you remember?

  • Name the two groups instruments are sorted into for the control-and-performance method, and give an example of each
  • Describe two sensory illusions that can mislead a pilot in cloud
  • List the actions to take if you find yourself in cloud unexpectedly, in order
  • State the recovery sequence for a nose-low unusual attitude, in order
Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Summary

Topic Key point
Control & performance Control instruments (AI, power) show what you've set; performance instruments show the result — scan continuously, don't chase
Illusions The leans, graveyard spiral, somatogravic — all caused by the inner ear once vision is gone. Trust the instruments
Avoiding & escaping IMC Plan and set minimums to avoid it; if it happens anyway: control, turn back, tell someone
Unusual attitudes Airspeed tells you which type; recover power, then wings level, then pitch
Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

178 seconds

That's the average time a VFR pilot who flew into cloud stayed in control.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Read the panel. Call the recovery.

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Objectives Check

Can you:

  • Describe the control-and-performance method, and explain why a continuous scan matters?
  • Describe at least three sensory illusions that can mislead a pilot?
  • Explain the dangers of inadvertent IMC entry, and outline the actions to take?
  • Describe the instrument indications and recovery for a nose-high and a nose-low unusual attitude?
  • Feel ready to experience all of this in the air today?
Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Arrival

Basic Instrument Flight — Theory: Reading the Panel, Illusions, IMC and Unusual Attitudes

Questions?

Any questions before the pre-flight brief?

This lesson pairs with a pre-lesson workbook the student completes beforehand (self-study videos/articles + fill-in questions) covering instrument power sources, instrument checks and serviceability, instrument lag, and compass turning/acceleration errors. Confirm it's done at the start — this deck builds on it rather than re-teaching it from scratch. This live session covers the topics that need real discussion and judgement: reading the panel as a system (control and performance instruments, scan technique), the sensory illusions that can mislead a pilot without outside visual reference, avoiding and escaping inadvertent IMC, and recognising and recovering from an unusual attitude. This lesson also revises and assesses a long list of foundational skills (communication, pre-flight actions, start/stop, taxiing, pre-take-off, radio and transponder operation, post-flight) — those are folded into the pre-flight and in-flight notes rather than theory, since they are consolidation of existing skills, not new content.

Let the student answer from their own experience before moving on — most people have a disorientation story of some kind. - Spinning like this is forcing a vestibular illusion - a very stong one!

An aeroplane in cloud, fog, or over featureless terrain at night removes exactly that visual reference. Lead in: so how does a pilot fly accurately without it?

About 34 minutes, leaving headroom in the 0.8 hr theory window — the pre-lesson workbook has already carried some of the load.

These map to CASA lesson-26 elements IFF.1 (determine/monitor instrument serviceability), IFF.2 (perform manoeuvres using full instrument panel), IFF.3 (recover from upset situations/unusual attitudes) — all at performance standard 3 (introductory) this lesson, underpinning knowledge IFF 4(a-c). This is first exposure, not an assessed competency yet.

Click Direct-To to arrive at Flying by the Instruments.

This is the revision element for the lesson — it revises the pre-lesson workbook rather than a previous lesson. Confirm it was actually completed and clear up anything that didn't land before moving on. If it wasn't done, take a few extra minutes here to cover the workbook content verbally rather than skip it.

CASA underpinning knowledge IFF 4(b): attitude and power requirements to achieve specified flight profiles. This is the standard "control and performance" concept of attitude instrument flying — set, hold, confirm.

On your training aircraft's actual panel, point to the power gauge itself so the student sees where the other control instrument sits relative to this six-pack photo.

Demo script: on the ground, point to each instrument in your aircraft's actual panel layout in scan order and have the student repeat the sequence back before flying.

Click Direct-To to arrive at Trust Your Instruments.

PHAK Ch 17 (Aeromedical Factors) covers the full "ICEFLAGS" set of illusions — these three are the ones most relevant to a training-aircraft RPL flight. Point keen students at the full list in the further reading below.

HF/NTS: undesired aeroplane state — prevention, identifying [NTS2 4(e)]. Keep this factual, not alarming — the point is a practical habit (trust the instruments), not fear.

Click Direct-To to arrive at Avoiding and Escaping IMC.

Statistic and case reference: ATSB "VFR into IMC" topic page (https://www.atsb.gov.au/taxonomy/term/385). For a fatal case study (handle sensitively — this one is recent and fatal): ATSB investigation AO-2025-056, VFR into IMC and controlled flight into terrain involving Cirrus SR20 VH-TEL, 12 km east of Braidwood/Percheron aircraft landing area NSW, 18 September 2025 (https://www.atsb.gov.au/investigations/ao-2025-056) — the pilot had flown from Bankstown via the Snowy Mountains to overhead Mallacoota before turning back toward Bankstown, encountering low cloud on return. Present the facts plainly, without dramatising — the safety point is the decision points, not the outcome.

CASA HF/NTS: threat and error management [NTS2 4(b)], situational awareness [NTS2 4(c)]. Ties to the PAVE / I'M SAFE checks the student already runs each flight — weather planning and external pressure are exactly what those checks are for.

This is the CASA long-briefing item "actions upon inadvertent entry into IMC". It connects directly to today's assessed items C3.1/C3.3 (radio and transponder operation) and to the rate-one turn technique practised in the air exercise (IFF.2c).

Click Direct-To to arrive at Unusual Attitudes.

This connects to Lesson 18's spiral dive comparison table — same discriminator (the ASI), same underlying idea. Repeat that link out loud if the student flew Lesson 18.

FIM Ch 17 background: nose-high recovery is simultaneous full power + roll wings level + ease forward; nose-low recovery is close throttle (if fast) + roll wings level, then ease out of the dive. This is the same "wings level before you pitch" principle taught for the spiral dive in Lesson 18 — deliberately repeat it here.

CASA IFF.2: perform manoeuvres using full instrument panel. Limited/partial-panel technique (flying with the AI or DI covered) is beyond RPL scope and introduced later at the FIR/CPL level — mention this only if a keen student asks.

Click Direct-To to arrive at the recap.

Question-list recall element — the filled summary table on the next slide is the answer key. If you're short of time, or the student is answering these confidently, skip the summary table and go straight to the video and the unusual-attitude panel that follow — that is the part of this lesson that saves lives, and it's worth the remaining minutes.

CASA's "'178 seconds to live' — updated". The number comes from an often-quoted 1954 University of Illinois study in which non-instrument-rated pilots put into simulated cloud lost control in an average of 178 seconds. Treat it as the scale of the problem, not a precise figure — the point is that it's minutes, not tens of minutes. Let it run. Don't fill the silence afterwards — go straight into the panel on the next slide, which is the answer to "so what do I actually do?".

The drill, run it several times: 1. Ask the student to look away, then press **Set unusual attitude** — the panel covers itself for the countdown and uncovers on a developed attitude. 2. Student says out loud, in this order: nose high or low, wings which way, speed doing what. 3. Then the recovery, in order, before touching anything — power, wings level, pitch. 4. **Reveal** shows what it actually was, with height lost and peak speed. 5. **Show recovery** plays the correct recovery back for comparison. **Hold** freezes the panel if you want to talk through the scan — use it as a teaching pause, not to make the exercise easier; the time pressure is doing real work. Let one run go all the way to the ground at least once. Watching 3,000 ft disappear in under a minute makes the point about hesitation better than any warning does. Add `severity="severe"` for a keen student, or pin `scenario="nose-high"` / `"nose-low"` to drill one case. Whatever wording the student settles on for their recovery call, use it as the callout during the hood exercise in the air today.